Haldane's Rule and Darwin's Corollary to Haldane's Rule are the observations that heterogametic F1 hybrids are frequently less fit than their homogametic siblings, and that asymmetric results are often obtained from reciprocal hybrid crosses. In Caenorhabditis, Haldane's Rule and Darwin's Corollary have been observed in several hybrid crosses, including crosses of Caenorhabditis briggsae and C....

Genic male sterility (GMS) has great potential for heterosis exploitation in sesame (Sesamum indicum L.). Two spontaneous male-sterile plants were discovered in a Chinese sesame cultivar (Zhuzhi 4) in 2006. By consecutive sib mating with fertile plants from Zhuzhi 4, a new sterile line, D248A, was developed. Anatomy studies showed that D248A has thin, small and greenish anthers on which there a...

The feeding preferences of individuals within a single species of marine consumer can differ because of variation in ontogeny, physiological state and environmental conditions; yet genetic variation can also play a central (largely undescribed) role. This study describes the nature of the genetic inheritance of feeding preference in the herbivorous amphipod Ampithoe longimana. Two populations k...

The formation of hybrids among closely related species has been observed in numerous plant taxa. Selection by pollinators on floral traits can act as an early reproductive isolating barrier and may be especially important when there is overlap in distribution and flowering time. In this study, we use Quantitative Trait Locus (QTL) mapping based on 293 codominant SNP markers in an F2 population ...

F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics o...

The nature of epistatic interactions between genes encoding interacting proteins in hybrid organisms can have important implications for the evolution of postzygotic reproductive isolation and speciation. At this point very little is known about the fitness differences caused by specific closely interacting but evolutionarily divergent proteins in hybrids between populations or species. The int...

Tilapia species exhibit a large ecological diversity and an important propensity to interspecific hybridisation. This has been shown in the wild and used in aquaculture. However, despite its important evolutionary implications, few studies have focused on the analysis of hybrid genomes and their meiotic segregation. Intergeneric hybrids between Oreochromis niloticus and Sarotherodon melanothero...

Linkage maps are widely used to investigate structure, function, and evolution of genomes. In speciation research, maps facilitate the study of the genetic architecture of reproductive isolation by allowing identification of genomic regions underlying reduced fitness of hybrids. Here we present a linkage map for European newts of the Lissotriton vulgaris species complex, constructed using two f...

We tested the hypothesis that a genetically determined increase in renal or-adrenergic receptor density might be a pathophysiologically important factor in the spontaneously hypertensive rat model of genetic hypertension. In a first study, we compared renal a,and <*t-adrenergic receptor density with systolic blood pressure in 45 rats of an F2 generation of Wistar-Kyotox spontaneously hypertensi...

A number of studies have been conducted on hybridization between transgenic Brassica napus and B. rapa or backcross of F1 hybrid to their parents. However, trait changes must be analyzed to evaluate hybrid sustainability in nature. In the present study, B. rapa and transgenic (BrAGL20) B. napus were hybridized to verify the early flowering phenomenon of F1 hybrids, and F1 hybrid traits were ana...